1. Field of the Invention
The present invention relates to a lock in which at least one pin means is disposed.
2. Brief Description of the Prior Art
Some of traditional locks comprise a casing having a tubular hole defined longitudinally therein for receiving a cylindrical rod rotatably disposed therein. The casing and the rod each have a plurality of receiving holes in alignment with each other for biasedly receiving a plurality sets of pin means therein. Generally, each of the pin means consists of two cylindrical pins which are located in alignment with each other, or each of the pin means is composed of two hollow cylindrical pins which are located in alignment with each other, each of the two hollow cylindrical pins having a central hole defined therein for receiving a cylindrical pin. The cylindrical rod has a key hole defined therein which communicates with the receiving holes of the cylindrical rod such that a part of each pin means extends into the key hole. A suitable key has an engaging means which is generally formed to be a serrated configuration or recesses or cone-shaped recesses or protrusions. When a suitable key is inserted into the key hole, the engaging means can adjust the locations of the pin means so as to adjust the contacting surface of each pair of two cylindrical pins of each set of the pin means (or two hollow cylindrical pins) coincides with the inter-connecting surface between the casing and the cylindrical rod such that the lock can be unlocked and the cylindrical rod can be rotated corresponding to the casing by rotating the key.
The factors considered to ensure a safety feature and the numbers of assemblies of the pin means include: the positions and numbers of every single pin means which is treated as an unit, such as the configuration, the length and the size of each of the cylindrical pins or hollow cylindrical pins; the configuration and size of the key hole in the cylindrical rod, the configuration and structure of the key and by what manner the engaging means of the key is disposed.
Although these factors have been considered and utilized by the manufacturers in the art, it is not good enough for a need of having a safe and expandable lock.